Ability of GCMs to represent climate during pilgrimages in Ethiopia

Climate influences human actions, including our cultural practices. Pilgrimages provide an important way for people to strengthen their spiritual or religious beliefs and are usually manifested as a journey to a sacred place, with Ethiopia notable for famous religious destinations. The conditions experienced by pilgrims are likely to change in a warming world, potentially making such journeys more arduous. Climate models struggle to reproduce key features of African climate with areas of extreme orography, such as the Highlands of Ethiopia, posing a significant challenge. Our study assesses (i) the sensitivity of climate parameters to the length of time considered within the dry season (Bega) and (ii) the ability of three global climate models, GCMs (HadGEM3-GC31-MM, CMCC-ESM2 and NorESM2-MM) to capture climate by comparing it to the ERA5 reanalysis and CHIRPS datasets. Results show the importance of adjusting the length of time so it is relevant to the process or social practice being studied, which might not map onto the three-month seasons traditionally used in climate research. Three of the six climate parameters assessed (minimum and maximum daily temperature and the number of rain days greater 1 mm) were successfully captured by the GCMs. This means these parameters could be used to assess future impacts of climate change on the climate experienced by pilgrims in Ethiopia.